464d1a78fb
Convert the PDA code to use %fs rather than %gs as the segment for per-processor data. This is because some processors show a small but measurable performance gain for reloading a NULL segment selector (as %fs generally is in user-space) versus a non-NULL one (as %gs generally is). On modern processors the difference is very small, perhaps undetectable. Some old AMD "K6 3D+" processors are noticably slower when %fs is used rather than %gs; I have no idea why this might be, but I think they're sufficiently rare that it doesn't matter much. This patch also fixes the math emulator, which had not been adjusted to match the changed struct pt_regs. [frederik.deweerdt@gmail.com: fixit with gdb] [mingo@elte.hu: Fix KVM too] Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Ian Campbell <Ian.Campbell@XenSource.com> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Zachary Amsden <zach@vmware.com> Cc: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org>
60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
#ifndef _I386_PTRACE_H
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#define _I386_PTRACE_H
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#include <asm/ptrace-abi.h>
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/* this struct defines the way the registers are stored on the
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stack during a system call. */
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struct pt_regs {
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long ebx;
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long ecx;
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long edx;
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long esi;
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long edi;
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long ebp;
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long eax;
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int xds;
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int xes;
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int xfs;
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/* int xgs; */
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long orig_eax;
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long eip;
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int xcs;
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long eflags;
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long esp;
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int xss;
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};
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#ifdef __KERNEL__
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#include <asm/vm86.h>
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#include <asm/segment.h>
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struct task_struct;
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extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code);
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/*
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* user_mode_vm(regs) determines whether a register set came from user mode.
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* This is true if V8086 mode was enabled OR if the register set was from
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* protected mode with RPL-3 CS value. This tricky test checks that with
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* one comparison. Many places in the kernel can bypass this full check
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* if they have already ruled out V8086 mode, so user_mode(regs) can be used.
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*/
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static inline int user_mode(struct pt_regs *regs)
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{
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return (regs->xcs & SEGMENT_RPL_MASK) == USER_RPL;
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}
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static inline int user_mode_vm(struct pt_regs *regs)
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{
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return ((regs->xcs & SEGMENT_RPL_MASK) | (regs->eflags & VM_MASK)) >= USER_RPL;
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}
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#define instruction_pointer(regs) ((regs)->eip)
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#define regs_return_value(regs) ((regs)->eax)
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extern unsigned long profile_pc(struct pt_regs *regs);
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#endif /* __KERNEL__ */
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#endif
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